<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="application/javascript">

    </script>
    <style type="text/css">
        .box{
            height: 20px;
            background:100% repeat-y green url("img/bg.png");
        }
    </style>
</head>
<body>
<div class="box"></div>
</body>
</html>